The present invention relates to a vehicle suspension apparatus for controlling a change in position of a vehicle along its longitudinal direction when the vehicle is rapidly accelerated.
In general, a shock absorber having a damping shock absorber and a spring is inserted between the vehicle body and each wheel. Such a suspension apparatus is provided for each of the front and rear wheels. The spring supports the vehicle weight and mainly absorbs a static input, while the shock absorber mainly absorbs a dynamic input. The shock absorber further protects the vehicle body from vibration near a neutral vehicle height position by an external force.
However, in this suspension apparatus, when a continuous load acts on the rear wheels as the vehicle is rapidly accelerated, the rear portion of the vehicle body is moved downward while the front portion thereof is moved upward. When acceleration is decreased, the front portion is moved downward while the rear portion is moved upward, thereby discomforting the driver and passengers and degrading driving stability.
In view of problem, another conventional shock absorber with a damping force switching mechanism is known. When the vehicle is rapidly accelerated, the damping force of the shock absorber is increased to decrease a change in vehicle position.
In the above shock absorber, a speed of change in vehicle position can be decreased upon rapid acceleration of the vehicle, even if the damping force of the shock absorber is increased. However, the absolute value of the change in vehicle position cannot be decreased if an acceleration state is kept for a long period of time, thus failing to provide a satisfactory effect.